System and method to detect a failed shear bolt supporting a concave of an agricultural combine

ABSTRACT

A system and method for detecting existence of a failed or broken shear bolt supporting all or a portion of a concave of a threshing system of an agricultural combine and utilizing information relating to rates of movement and absence of movement of a concave to determining the existence and non-existence of a failed or broken shear bolt supporting the concave. More particularly, the present system and method is operable to diagnose existence of a broken shear bolt from a rapid downward movement of the concave and non-movement of the concave during operation of a driver for repositioning the concave. Also, existence of a false broken concave condition can be diagnosed by movements of the concave responsive to operation of the driver.

This divisional application claims priority under 35 U.S.C. § 120 fromco-pending U.S. patent application Ser. No. 10/978,897 filed on Nov. 1,2004 by David N Heinsey et al. with the same title, the full disclosureof which is hereby incorporated by reference.

TECHNICAL FIELD

This invention relates generally to a system and method for detectingexistence of a failed or broken shear bolt supporting all or a portionof a concave of a threshing system of an agricultural combine and, moreparticularly, to a system and method which utilizes information relatingto rates of movement and absence of movement of a concave to determinethe existence and nonexistence of a failed or broken shear bolt.

BACKGROUND ART

Commonly, one or more shear bolts are utilized in support of a concaveor a section of a concave extending partially around a bottom portion ofa rotor of a threshing system of an agricultural combine, which shearbolt or bolts are designed to fail or break to allow the concave orconcave section to fall away from the rotor when large slugs of cropmaterial and/or hard foreign objects enter the space between the concavesegment and the rotor. This is intended to prevent damage to thethreshing system, but also results in degraded performance of thethreshing system Typically, if a shear bolt breaks to allow a segment ofthe concave to fall away from the rotor, contamination in the cleangrain and/or discharge of larger pieces of crop material from the cropresidue system of the combine will be noticed. Often, the investigationinto the decreased performance will begin or will be concentrated on thecleaning system of the combine, such that excessive machine downtime maybe required before the failed concave shear bolt is discovered.

Thus, what is sought is a manner of detecting a failed or broken concaveshear bolt automatically and quickly, and which is simple and economicalto implement.

SUMMARY OF THE INVENTION

What is disclosed is a system and method for detecting a failed orbroken shear bolt supporting a concave of a threshing system of anagricultural combine, which provides one or more of the sought afterbenefits set forth above.

According to a preferred aspect of the invention, the threshing systemincludes a rotatable rotor and at least one concave segment extendingaround a lower region of the rotor in spaced relation thereto. Onelongitudinally extending edge of the concave segment is preferablepivotally or hingedly supported to allow movement of the concave segmentupwardly and downwardly in relation to the rotor. Such upward anddownward movement is preferably accomplished by a driver, which can be,for instance, but is not limited to, a rotary or linear electric motoror actuator, a fluid cylinder, or the like, connected to the concave bya linkage including a shear bolt designed to fail or break when a forceis applied against the concave urging it away from the rotor and of asufficient magnitude to potentially damage the rotor and/or concave. Thesystem also preferably includes a device or sensor such as, but notlimited to, a potentiometer or Hall Effect sensor, for sensing ordetermining a position of the concave relative to the rotor or anothersuitable location.

According to a preferred method of operation of the system, the positionof the concave is monitored and, if a rate of change of the position ina downward direction exceeds a predetermined value, it is determinedthat the shear bolt is failed or broken, and a signal representativethereof is outputted. If the concave is at or near its lowest positionwhen the driver is operated to raise the concave, the position thereofwill be monitored and, if the position does not change accordingly, itwill be determined that the shear bolt is broken.

Additionally, if the shear bolt is indicated as being broken and thedrive is operated and corresponding movement of the concave isdetermined, the broken shear bolt condition will be determined to befalse.

As a result, both the existence and absence of a failed or broken shearbolt can be determined according to the system and method of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified schematic representation of a rotor and concaveof a threshing system of an agricultural combine, showing elements of asystem including a representative driver controllably operable f ormoving the concave relative to the rotor, and a linkage including anintact shear bolt connecting the driver to the concave, the system beingoperable for detecting failure or breakage of the shear bolt accordingto the invention;

FIG. 2 is another simplified schematic representation of the rotor andconcave of FIG. 1, showing the shear bolt broken to disconnect thedriver from the concave and allow the concave to fall away from therotor;

FIG. 3 is a high level flow diagram of steps of the method of operationof the system for detecting failure or breakage of the shear bolt ofFIGS. 1 and 2;

FIG. 4 is another high level flow diagram of steps of the method ofoperation of the system for detecting failure or breakage of the shearbolt of FIGS. 1 and 2;

FIG. 5 is still another high level flow diagram of steps of the methodof operation of the system for detecting failure or breakage of theshear bolt of FIGS. 1 and 2; and

FIG. 6 is another high level flow diagram of steps of a method ofoperation of a system for detecting failure or breakage of the shearbolt of FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, in FIGS. 1 and 2, representativethreshing apparatus 10 of a threshing system of an agricultural combineis shown. Threshing apparatus 10 includes a cylindrical rotor 12rotatably driven about a central longitudinal axis 14 therethrough.Threshing apparatus 10 also includes at least one semi-cylindricalshaped concave 16 positioned so as to extend around a lower region ofrotor 12 of all or a segment of the length thereof. Here, it should berecognized or understood that concave 16 is intended to berepresentative of a concave that extends longitudinally along only aportion of the length of rotor 12, or along the entire length thereof.Concave 16 is shown supported along one longitudinally extending edgethereof, by a pin 18, for pivotal movement relative to rotor 12, asgenerally denoted by arrows A. In this regard, in FIG. 1, concave 16 isshown in what would be considered an operative position in spacedrelation to an outer cylindrical surface of rotor 12, for threshing andseparating grain introduced with other crop material in the spacebetween rotor 12 and concave 16. The separated grain would then passthrough holes or perforations in the surface of concave 16 so as tosubsequently fall or be conveyed into a cleaning system (not shown) ofthe combine for further processing in the well known manner. Theopposite longitudinally extending edge of concave 16 is supported by alinkage assembly 20 including a link arm 22 supported for rotation on apin 24 connected to a frame or other structural member of the combinefor rotation thereabout, as denoted by arrows B, a distal end 26 of linkarm 22 being pivotally connected by a bolt 28 to a link 30 which, inturn, is connected by a shear bolt 32, to concave 16. Link arm 22 isadditionally connected to a driver 34 including a rod 36 extendableupwardly, and retractable downwardly, as denoted by arrows C, forrotating distal end 26 of link arm 22 upwardly and downwardly, asdenoted by arrows B, for raising and lowering link 30 and concave 16 asdenoted by arrows A.

Here, it should be noted and understood that driver 34 is representativeof a wide variety of drivers and actuators that could be used inconnection with concave 16 for raising and lowering it to achieve adesired spacing in relation to rotor 12, which drivers and actuators caninclude, but are not limited to, electric rotary and linear motors oractuators, fluid cylinders and the like. It should also be understoodthat linkage assembly 20 is but an example of a wide variety ofdifferent linkage assemblies and arrangements and other apparatus thatcan be used in connection between a driver, such as driver 34, andconcave 16 for effecting movement of concave 16.

Referring more particularly to FIG. 1, driver 34 is controllablyoperable by a control system 38 preferably including a suitablecontroller 40 such as a conventional processor based controllerincluding a memory 42 and connected by one or more conductive paths 44to driver 34 and a signal or display device 46, and also to a positionsensor 48 associated with concave 16 for determining a position thereofrelative to rotor 12 or another location and outputting informationrepresentative thereof to controller 40. Here, position sensor 48 is inconnection with pin 18 so as to be operable for determining a pivotableor rotational position of concave 16 about an axis of rotation of pin18, although it should be understood that a wide variety of other sensordevices, such as a proximity sensor or the like, could be used fordetermining the position of concave 16. More particularly in thisregard, position sensor 48 can be a commercially available andconventionally operable potentiometer or Hall Effect sensor, as just twoexamples.

As noted previously, in FIG. 1, concave 16 is shown at an operativeposition in a selected spaced relation to rotor 12, for separating grainfrom other crop material introduced into the space by the rotation ofrotor 12 in the well known manner. In contrast, in FIG. 2, concave 16 isshown dropped or fallen from link 30 of linkage assembly 20 to a non orless operative position, as a result of failure or breakage of shearbolt 32 in such a manner so as to cause disconnection of link 30 fromconcave 16. Here, by the term “failure”, what is meant is a shearing orother breakage of shear bolt 32 in such a manner that concave 16 isdisconnected or disengaged from link 30, so as to be capable of freelyfalling downwardly away from rotor 12 to thereby enlarge the spacetherebetween. This will typically occur as a result of induction orpassage of a large slug or slugs of dense crop material into the spacebetween rotor 12 and concave 16, or the induction of hard foreignobjects into the space, which, at least partially as a result of therotation of rotor 12, will apply a radially outwardly directed forceagainst concave 16, which will be translated thereby and concentratedagainst the one or more shear bolts 32, which will have a predeterminedload carrying capability. Thus, if the force applied against concave 16and translated to the one or more shear bolts 32 exceeds the designlimit of the shear bolt 32, the shear bolt will fail or break, thusreleasing concave 16 to fall away from rotor 12, in the well knownmanner.

It has been observed that if a shear bolt 32 is broken by application ofa force thereagainst exceeding the load limit thereof, the applied forcecan cause concave 16 to rapidly or abruptly fall away from rotor 12, soas to result in a rate of change in the position of concave 16 whichwill be greater than that which will typically occur as a result ofnormal movements of concave 16 by driver 34. Information representativeof such rapid rate of change will be outputted by position sensor 48 tocontroller 40, which can be programmed to compare the sensed rate ofchange to one or more stored values which can be representative of, forinstance, a maximum rate of normal downward movement of concave 16 bydriver 34. As a result, if the sensed rate of positional change exceedsthe stored value, controller 40 can be programmed to determine that abroken shear bolt condition exists. Controller 40 can then storeinformation representative of this condition in memory 42 and, ifdesired, output a warning or alarm signal to a display, such as display46, and/or to a warning alarm or the like for alerting the combineoperator or other personnel.

As another aspect of the invention, if concave 16 is at a lower extremeor limit of its travel relative to rotor 12 and breakage of shear bolt32 occurs, the rapid falling of concave 16 may not occur. However,subsequently, when driver 34 is operated for raising concave 16, if nocorresponding raising or change in position of concave 16 is sensed byposition sensor 48, for instance, for a specified period of time,controller 40 can be programmed to determine that a broken shear boltcondition exists and store information representative thereof and/oroutput a signal or alarm representative thereof, as desired.

Still further, if shear bolt 32 has been previously broken and repaired,or erroneously found to have been broken, controller 40 can operatedriver 34 to move concave 16 and, if a resultant positional change isdetected by position sensor 48, controller 40 can be programmed todetermine that shear bolt 32 is intact or functional, and storeinformation representative of that condition in memory 42 and/or outputa signal representative thereof or cancel a signal or alarm indicating abroken shear bolt condition.

Further in this regard, it should be noted that it is contemplated thatcontroller 40 can include one or more timers or clocks for timingoperation of driver 34, and movement and/or non-movement of concave 16,and that memory 42 can include a variety of registers for holdinginformation representative of the various times and positions of concave16. As examples, such timers can include an initialize shear boltvariables timer; an update previous concave position timer; and aconcave not moving timer. Such registers in memory 42 can include, forinstance, a current concave position register; and a previous concaveposition register, either or both of which can be written over asdesired. A flip-flop or flag register can also be utilized for storingan indication of a broken shear bolt condition.

Referring also to FIGS. 3, 4, 5 and 6, steps of a representative methodof operation of system 38 for testing for a broken shear bolt andoptionally verifying a broken shear bolt using the above referencedtimes and registers are set forth. In this example, driver 34 isrepresented by an electric motor. In FIG. 3, at block 50, the test isinitiated. At system startup, it is desirable for the initialize shearbolt variables timer to be set to one second. The process for this isinitialized at decision block 52 which determines whether the initializeshear bolt variables timer is not equal to zero, and a key voltage isless than a predetermined value, here, 9.0 volts. If both of theseconditions are present, controller 40 will proceed to set theinitialized shear bolt variables timer equal to one second, as denotedat decision block 54 and block 56. After the initialize shear boltvariables timer has been set equal to one second, or the key voltage isnot less than 9.0 volts, controller 40 will proceed to decrement theinitialize shear bolt variables timer by a value of one (equal to 10milliseconds), as denoted by block 58. Then, the controller will set theprevious concave position register equal to the current concaveposition; set the concave not moving timer equal to 5 seconds as denotedat block 62; and set the update previous concave position timer equal toone second as denoted at block 64.

Controller 40 will then proceed as denoted at A to end test block 66,then return to block 50 and follow this same sequence of steps as longas the initialize shear bolt variables timer is not equal to zero and/orthe key voltage is less than 9 volts. Controller 40 can cycle throughthis series of steps, including steps 54, 56 and 58, wherein theinitialize shear bolt variables timer will be decremented and reset, aslong as the key voltage is less than 9 volts. If the key voltage risesto 9 volts or greater, at block 54, controller 40 will bypass block 56and proceed to decrement the initialize shear bolt variables timer,reset the previous concave position to the current concave position, setthe concave not moving timer to 5 seconds, and set the update previousconcave position timer equal to one second, as set forth in blocks 58,60, 62 and 64, then cycle through blocks 66 and 50 and 52, until theinitialize shear bolt variables timer has been decremented to zero andthe key voltage has remained at 9 volts or above.

At block 52, once the initialize shear bolt variables timer is equal tozero, and the key voltage is still 9 volts or above, controller 40 willproceed from block 52, as denoted at C, to decision block 68 in FIG. 4,wherein controller 40 will determine whether a concave shear bolt brokenflag is equal to one, denoting a broken condition. If, at block 68, itis determined that the flag is not equal to one, controller 40 willproceed as denoted at D, to block 70 in FIG. 5 wherein it will set theconcave shear bolt failure alarm equal to an alarm off condition.Controller 40 will then proceed to decision block 72 to determinewhether the previous concave position is less than the current concaveposition. Here, it should be noted that a lesser position value willdenote a concave position closer to the rotor, whereas a greater concaveposition will denote a position farther from the rotor. If, forinstance, referring to FIGS. 1 and 2, driver 34 has not been operated tomove the concave, and controller 40 has most recently executed sequenceof steps 58-64, the previous concave position will have been set equalto the current concave position. As a result, at step 72, the previousconcave position should still equal the current concave position. If, onthe other hand, driver 34 has been actuated for moving the concave up ordown, the previous and current positions should differ accordingly.Also, at the run speed of controller 40, and the operating speed ofdriver 34 for moving the concave, any change in concave position equalto or greater than 5 millimeters between sequential executions of step72, can be presumed to be indicative of an abrupt shear bolt failure andresultant fall of the concave.

Thus, at decision block 72, if the previous concave position is lessthan the current concave position, controller 40 will proceed todecision block 74 and determine whether the current concave positionminus the previous concave position is greater than or equal to 5millimeters. If not, any difference will be considered normal andcontroller 40 will proceed on to the next step. However, if there hasbeen a large change in concave position, controller 40 will proceed toset the concave shear bolt broken flag equal to one which isrepresentative of a broken shear bolt condition, as denoted at block 76.Here, it should be noted that the 5 millimeter value is intended to be arepresentative value only, and is not intended to limit the presentinvention.

Controller 40 will then proceed to calculate a concave motor current, asdenoted at block 78, in preparation for testing whether the concavemoves when driver 34 is operated to raise the concave. At decision block80, controller 40 determines the presence of necessary conditions forthis test, including whether the concave motor (driver 34) is energizedto raise the concave, a concave bridge output is not an error, concavemotor current is less than 5 amps, and the current concave position isequal to the previous concave position. If these conditions are notpresent, controller 40 will set the concave not moving timer to aninitial value, here, 5 seconds, as denoted at block 82. Subsequently,controller 40 will determine whether the concave not moving timer isequal to zero, at decision block 84. If controller 40 has proceededthrough steps 80 and 82, the concave not moving timer will be set at 5seconds, such that at decision block 84, it will be determined that theconcave not moving timer is not equal to zero, and controller 40 willproceed to the steps contained in FIG. 6. On the other hand, if all ofthe conditions of decision step 80 are present, controller 40 willdecrement the concave position not changing timer by one (10milliseconds), as denoted at block 86. Then, controller 40 will proceedto determine whether the concave not moving timer is equal to zero, andif yes, will proceed to set the concave shear bolt broken flag to one,representing a broken shear bolt condition, as denoted at block 88 thenproceed as denoted at B to execute the steps of FIG. 6.

Here, essentially, if the current concave position equals the previousconcave position for 5 seconds of operation of driver 34 for raising theconcave, controller 40 is determining that a broken shear bolt conditionexists. This is a useful test to be conducted when the concave may havebeen at its lowest position at the time of shear bolt breakage.

Referring also to FIG. 6, after execution of the step of block 84 or thestep of block 88, controller 40 will proceed to decision block 72 todetermine whether the update previous concave position timer is equal tozero, at decision block 93. If no, it will proceed to decrement theupdate previous concave position timer by one (10 milliseconds), asdenoted at block 92 and proceed to the end of the test. If the updateprevious concave position timer is equal to zero, the controller willset the previous concave position equal to the current concave position,as denoted at block 94. Then, at block 96, the update previous concaveposition timer will be set equal to one second and the test will end, asdenoted at block 66.

Referring again to FIGS. 3 and 4, after initiating the test, as denotedat block 50; determining that both conditions of decision block 52 arenot present; and having a concave shear bolt broken flag conditionequals one (indicating a broken shear bolt condition) controller 40 willproceed through a sequence of steps to determine whether the brokenshear bolt flag setting is erroneous. Here, at decision block 98,controller 40 determines whether the thresher is engaged. If yes, apriority 3 concave shear bolt failure alarm is outputted, as denoted atblock 100. This is a high level alarm condition. If, on the other hand,at block 98 it is determined that the thresher is not engaged andrunning, a priority 1 concave shear bolt failure alarm will beoutputted, as denoted at block 102. Then, controller 40 will determinewhether the concave motor is energized, at decision block 104. If not,it will proceed, as denoted at B, to the sequence of steps shown in thediagram of FIG. 6. If, at block 104, it is determined that the concavemotor is energized, controller 40 will proceed to determine whether thecurrent concave position is not equal to the previous concave position,at decision block 106. If it is determined that the current and previousconcave positions are equal, it will be determined that the broken shearbolt condition is true, and controller 40 will proceed to execute thesteps of FIG. 6. If, at block 106, it is determined that the currentconcave position is not equal to the previous concave position, this isan indication that the concave has moved responsive to operation ofdriver 34. Accordingly, controller 40 will proceed to set the concaveshear bolt flag to a zero condition, indicating that the shear bolt isintact, as denoted at block 108. The previous concave position will thenbe set equal to the current concave position, as denoted at block 110,and controller 40 will proceed to execute the steps of FIG. 6.

From the proceeding discussion, it should be apparent that controlsystem 38 is operable according to the steps of the present invention,to diagnose a shear bolt failure or breakage condition as a result of anabrupt or rapid downward movement of the concave, as denoted by thesequence of steps 70, 72, 74 and 76. Additionally, if the concave is ator adjacent to the bottom of the range of normal positions thereof, abroken shear bolt condition can be diagnosed by the steps 80, 82, 84 and86. Still further, if a broken shear bolt condition flag exists, theexistence of a broken shear bolt, or non-existence thereof, can bedetermined by the steps of FIG. 4.

As a result of the operating steps of the system according to thepresent invention, a shear bolt failure condition can be accurately andquickly diagnosed and determined using the components used for movingand determining the position of the concave.

It will be understood that changes in the details, materials, steps, andarrangements of parts which have been described and illustrated toexplain the nature of the invention will occur to and may be made bythose skilled in the art upon a reading of this disclosure within theprinciples and scope of the invention. The foregoing descriptionillustrates the preferred embodiment of the invention; however,concepts, as based upon the description, may be employed in otherembodiments without departing from the scope of the invention.Accordingly, the following claims are intended to protect the inventionbroadly as well as in the specific form shown.

1-6. (canceled)
 7. A system for detecting a broken shear bolt supportinga concave of an agricultural combine, comprising: a device operable forperiodically determining a position of the concave and storing a valuerepresentative of the position in a memory; and a processor operable fordetermining a rate of change of the stored value over a plurality of theperiods and comparing the determined rate of change to a predeterminedvalue and, if the rate of change exceeds the predetermined value, thendetermining that a broken shear bolt condition exists.
 8. The system ofclaim 7, wherein the processor will determine the rate of change onlywhen the stored value exceeds a predetermined minimum value.
 9. Thesystem of claim 8, further comprising a driver operable for moving theconcave and, if the stored value is less than the predetermined value,when the driver is operated for raising concave, the processor willmonitor the position of the concave over a time period and, if theconcave has been raised by less than a predetermined amount during thetime period, will determine that a broken shear bolt condition exists.10. The system of claim 7, further comprising a driver controllablyoperable for moving the concave and, if a broken shear bolt conditionhas been determined and the driver is being operated, the processor willdetermine if the concave is moving and, if the concave is moving, thenthe processor will determine that a broken shear bolt condition does notexist.
 11. The system of claim 7 further comprising a device connectedto the processor operable for outputting a signal, the processor beingoperable such that when the processor determines that a broken shearbolt condition exists, the processor will cause a signal representativethereof to be outputted by the signal device. 12-13. (canceled)